Patent GB-304755-A (GB)
Title: Improvements in or relating to heat exchangers
IPC: F28D17/00
Filed: 1928-12-10
Abstract: 304,755. Milliken Bros. &. Blaw- Knox, Ltd., (Assignees of Dyrssen, W.). Jan. 26, 1928, [Convention date]. Regeneraters.-In multi-chamber reversible, regenerators the valves for different chambers through which the same gas is passing are operated out of phase with one another and at such relative rates that the total resistance, to gas flow of the chambers and valves is substantially constant. A series of chambers 7 contain banks of heat exchanging material H1, H2, H3 of different heat-resisting qualities, e.g. the bank H1 at the hot end may comprise sheets of steel of high chromium content, the bank H2 of steel containing less chromium and the bank H3 of ordinary steel. The chambers 7 communicate with a hot gas flue 4 through gas inlet, valves 9, the rods 11 of which also carry the gas outlet, valves 14 leading to a waste gas flue 16. Cold air from a conduit 17 is admitted to the chambers 7 by valves 20 en rods 19 which also carry the hot air outlet valves 22. The valve rods 11, 19 extend through the top wall of the regemerator and are engaged by forks 29 on reversing rocker arms 30 operated by cams 35 on a shaft 36 continuously rotated by a motor 38. Pins 31 on the rocker arms 30 are adapted to seat in brackets 32 and the cams 35 act upon rollers 34, 34<1> carried by upstanding portions 33 of the arms. The cams are so positioned on the shaft that the valves are operated out of phase by 120‹ as shown in Fig. 4, in which the curves g<1>-g<3> show the movements of the gas valves and curves g<1>-g<3> the movements of the air valves, and are so shaped that the opening and closing movements are not made with uniform velocity but are arranged so that the total resistance to the now of air or gas through the apparatus is maintained constant. Thus at the line XX, Fig. 4, the air valves of the chambers 2, 3 are partially open by amounts x<2>, x<3> less than the openings corresponding to uniform speed of operation, shown by the broken lines 40, to compensate for the decreased resistance caused by the chambers 2, 3 being temporarily operated in parallel and the air velocity being therefore lower than when the air is passing through one chamber only. The valves are operated by pins 10. 15, 21, 23 fixed to the valve rods and passing through elongated slots in the valve necks arranged so that the valve 14 seats before the valve 9 and the valve 22 before the valve 20. The timing is such that the valve 20 is opened before the valve 9 is fully closed so that for a short period during the reversal valves 14, 22 will be closed while valves 20, 9 are open and the air under pressure scavenges the chamber. The heat exchanging bodies may comprise steel sheets 48 bolted together and having notches 43 by which they are hung from brackets 42; at the cool end the bodies may rest on bars 44. A door 45 renders the bodies accessible for cleaning, the brickwork 46 being removable, and the plates may be shaken to remove dust &c. The division wall between the chambers 7 comprises spaced plates 47 covered by brickwork 48, air being circulated between the plates to cool them. The valves 9, 22 and their seats 8, 24 are made of high chromium. steel and the seat 8 is water cooled. Fig. 7 shows a modified form of heat exchange material comprising metal rods or wires bent to hairpin shape, hung upon bolts 53 and separated by bolts 54, 55 in a casing 52. Cleaning of the material is effected by steam pipes 56, Fig. 10, arranged between the banks and provided with nozzles 57, steam being supplied by a pipe 59 controlled by a valve 60. The pipe 56 is fixed to a spider 64 threaded through a. shell 58 and provided with a, handwheel 63 so that it may be rotated and is simultaneously moved axially. The pipes 56 pass through the partition walls between the chambers by gas-tight joints. Modifications with more than three chanbers are described in which the gas valves are open for longer periods than the air valves. Butterfly valves mav be used instead of the mushroom valves shown.